You can find more in-depth info online, but I tried to make it concise and in terms I understand.
Retinoblastoma:
Retinoblastoma is a rare cancer of the eye that arises from the retina, a thin layer of nerve tissue that enables the eye to see. Most cases involve only one eye (unilateral), but in some patients, both eyes may be involved (bilateral).
Retinoblastoma tumors are composed of immature cells known as retinoblasts. During gestation and early life, retinoblasts are able to actively divide. This is the process that helps make enough cells to populate the retina. As children grow older, their retinal cells undergo a process of maturation and are no longer able to divide. Since retinoblastoma tumors arise from retinoblasts, they generally develop during the first one to two years of life, and only very rarely after 5 years of age.
Children with the hereditary form of retinoblastoma are also at a slightly increased risk to develop tumors in the pineal gland (a small gland located in the brain) and possibly another cancer, such as a bone or muscle cancer, later in life.
The term 'Heritable':
Retinoblastoma occurs in two forms. A 'genetic' form (otherwise known as heritable) and a non-genetic form, known as non-heritable. 80% of children diagnosed with heritable retinoblastoma do not have a parent with retinoblastoma. As is the case with Leslie and Richard. The change in the gene occurred in either the egg or the sperm of one parent before conception. It happened before the egg split resulting in all 3 triplets having a mutation of the RB1 gene.
The term 'Bilateral':
Retinoblastoma exhibits itself in a few ways.
- Unilateral - only one eye is affected.
- Bilateral - Two eyes are affected.
- Trilateral - occurs when retinoblasts form in the pineal gland in the brain, independent of the cancer in the eyes. Trilateral can occur whether or not retinoblastoma was diagnosed early or in later stages. This is rare, but will be watched for with MRI.
- Extraocular - occurs when cancer spreads outside the eye, usually to the surrounding tissues, brain or bone marrow.
Prognosis:
Nearly 95 percent of children with retinoblastoma are cured. This is fabulous news, and due to advancements in medicine, as well as outstanding doctors who have dedicated their life to researching this cancer. Although, when they say "cured" this does not mean vision is restored. Nor does it mean the eye is preserved. Where there are tumors that have formed, there will be permanent vision loss due to calcium deposits and scarring. Attempts to preserve the eye involve treatments, which can have other significant side effects.
Again, this is not a comprehensive, detailed blog post on retinoblastoma. :) I was trying to put all the things I've read into a concise summary. If you want to find out more, there are many great resources. One of which is found here: Daisy Fund
Very well summarized Emily!
ReplyDeleteOne small correction: "trilateral" refers to retinoblastoma that forms in the pineal gland or suprasellar region of the brain - this tumour arises from cells in the brain that are very similar to retinal cells. Cancer that spreads outside the eye (usually to the surrounding tissues, brain or bone marrow) is called extraocular retinoblastoma. Extraocular Rb happens when the cancer is not diagnosed and treated early or when treatments are attempted to save a dangerous (E) eye, allowing microscopic cancer cells to escape unnoticed. Anyone wanting more detailed information about retinoblastoma will find an extensive resource at www.daisyfund.org (the red tab) - all the medical content was edited by the ophthalmologist treating Mason, Luke and Thomas.
Thanks Abby! Still learning here... :)
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